The specialized cytoplasm located at the posterior pole in Drosophila (called the pole plasm) contains the necessary components for both germ cell determination and abdomen assembly. Formation of this specialized cytoplasm is dependent upon and organized by the RNA and protein products of oskkas. Mutations in oskar cause a maternal effect phenotype in which the progeny of homozygous females lack both abdominal segmentation and germ cells. The function of oskar is dependent upon the localization of its RNA to the posterior pole of oocytes, where the oskar protein organizes the formation of the pole plasm. I propose to identify components of the pole plasm necessary for germ cell formation that are acting dowstream of oskar by obth genetic and biochemical means.